Automatic machine for making convergence cup electrodes for color television tubes



Dec. 23. 1969 c. o. MERCHANT 3 8 2 AUTOMATIC MACHINE FOR MAKING CONVERGENCE CUP ELECTRODES FOR COLOR TELEVISION TUBES Filed June 2, 1967 5 Sheets-Sheet 1 INVENTOR. FIG 2 CHESTER o. MERCHANT ATTORNEY Dec. 23. 1969 o. MERCHANT 3,485,124

AUTOMATIC MACHI INE FOR MAKING CONVERGENCE CUP ELECTRODES FOR COLOR TELEVISION TUBES Filed June 2, 1967 3 sheets-Sheet 2 FlC-lB INVENTOR. CHESTER .7. MERCHAI- QQMQMW ATTOHJEN Dec. 23. 1969 I c. o. MERCHANT AUTOMATIC MACH GENCE CUP TUBES INE FOR MAKING CONVER ELECTRODES FOR COLOR TELEVISION Filed June 2, 1967 3 Sheets-Sheet 5 FCC INVENTOR. CHESTER O. MERCHANT EZM 6? Gav-mom) ATTORNEY United States Patent 3,485,124 AUTOMATIC MACHINE FOR MAKING CONVERG- ENCE CUP ELECTRODES FOR COLOR TELE- VISION TUBES Chester O. Merchant, Owensboro, Ky., assignor to Kentucky Electronics, Inc., Owensboro, Ky., a corporation of Delaware Filed June 2, 1967, Ser. No. 643,221 Int. Cl. B26f 1/00 US. Cl. 83-182 8 Claims ABSTRACT OF THE DISCLOSURE A special machine is disclosed for making convergence cup electrodes for three gun color cathode ray tubes by punching a cylindrical workpiece with apertures adapted to receive beam convergence pole piece pairs extending inside the cylinder at three loctaions. The cylinders are positioned on hollow die posts at a plurality of stations on a rotary indexing table. A series of punching stations is provided with punches disposed radially to pierce the surface of the cylinder. At the punching stations a ram pushes an enveloping hood over the workpiece on the die post to engage and hold the workpiece in place. The hood carries laterally moving punches which are cammed to pierce the workpiece after the hood engages the workpiece and has reached a limited downward position over the workpiece.

This invention relates to manufacture of cylindrical cup-shaped convergence electrodes for three beam color cathode ray tubes and, more particularly, it relates to automatic machinery positioning and punching apertures for registering convergence pole pieces extending into a cylindrical electrode.

While convergence electrodes of the type made by this invention are well known in the art and have been made by various processes, considerable difiiculty has been encountered in meeting mechanical tolerance specifications imposed by the exacting requirements of uniformly processing three different electron beam through a complex electrode having many parts relatively positioned. Not only must the parts be relatively positioned with precision, but it is extremely difficult to do this while punching six or nine apertures through the sides of a thin cylindrical electrode wall. Two pole piece apertures are paired to extend on either side of the electron beam path and conventionally these apertures have been punched simultaneously by parallel punches. As a result the punches tend to be sprung apart, wear considerably, and frequently break because of the slippage on the outer cylindrical electrode body, and thus are hard to hold in position and aperture shape tolerance. Furthermore, even more significant, the roundness of the cylindrical electrode is distored and cannot be maintained uniformly from electrode to electrode.

Accordingly, it is an object of the present invention to produce improved equipment for more precisely manufacturing convergence cup electrodes for three beam color cathode ray tubes.

Another object of the invention is to provide automatic machinery for manufacture of convergence cup electrodes at high speeds without sacrificing precision.

Still another object of the invention is to provide automatic machinery for performing a sequence of several different precisely related and dimensioned shaping and punching opeartions upon a cylindrical cathode ray tube convergence electrode.

Thus, in accordance with the invention, an automatic machine is provided which characteristically forms in a "ice cylindrical electrode precvisely spaced and dimensioned apertures by means of radially moved punches piercing the cylindrical electrode as it passes from station to station about a rotary indexed table periphery. The cylindrical electrodes are placed over a hollow post which forms a die with the punches and which operates as a clamping member to receive a spring loaded matrix clamp carried by an axially moved hood assembly. Laterally movable punches are also carried on the hood assembly and are cammed into piercing engagement with the electrode cylinder by movement of the hood into a limiting axial position beyond the clamping engagement point at which the workpiece is held firmly in place.

Further structure features and objects of the invention will be discussed in the detailed description which follows with reference to the accompanying drawings, wherein:

FIGURE 1 is a perspective view of a convergence cup electrode assembly for a color cathode ray tube electron gun with FIGURE 1A showing the portion thereof punched by machinery provided in accordance with this invention;

FIGURE 2 is a diagrammatic sketch in plan view of the relative positions of various punches which form apertures in the convergence cup cylindrical body, with the cup and die shown in section;

FIGURE 3 is a partial view of an indexing table with a series of punching stations located thereabout; and

FIGURES 4 and 5 are elevation sketches, partly in section, of a punch station hood assembly in respective positions over an index table stationed with the die open and closed as viewed from section lines A-A or B-B in FIGURE 3.

Throughout the various figures, like reference characters are used to identify similar parts and facilitate comparison.

A convergence cup assembly is shown in FIGURE 1, wherein a cylindrical body 10 of thin non-magnetic metal forms a cup-shaped electrode with a closed bottom end 9 with three symetrically positioned apertures 11 therethrough for passing the three electron beams of a color cathode ray tube. Pairs of L-shaped magnetic pole pieces 12 are positioned through apertures 14 to span each of the three beam paths. This requires three pairs of apertures 14 each being spaced by to reside in separate sectors formed by generally V-shaped magnetic shield members 15. In one mounting arrangement, as shown in the drawing, these shield members extend through three apertures 16 spaced about the rim of the cup intermediate the pole piece pairs. The shields are welded in place by an L-shaped flange 8 extending alongside the outside of the cylinder 10 similarly to the pole piece 12. Accordingly, in such a configuration a total of nine apertures are required, which are formed in accordance with this invention in the manner diagrammatically shown in FIGURE 2.

It is important to pass each punch through the cylindrical workpiece body 10 radially in order to prevent any lateral stresses upon the punches caused by sliding over the cylindrical outer surface of the electrode. Thus, all the punches are relatively spaced about the cylindrical workpiece 10 to pierce it at the respective apertures 14, 16 and mate with a hollow apertured die post 17 over which the cylinder is resting. This die post 17 may take other forms but essentially it provides mating die apertures 18, etc. through which the punches push out blanks 19, etc. after piercing the walls of the cylindrical workpiece 10. Thus, the walls of the die 17 form a support tending to retain the cylindrical shape of the workpiece 10' after punching, and has a hollow interior 20 through which punched blanks 19 may be withdrawn. To clarify this drawing, the spacings are exaggerated.

Provided only the pole piece apertures 14 are required, such as when flanges 8 are welded to the inside surface of cup 10, a single punch 21 could be used to radially pierce the cup at the six diiferent locations in sequence by rotating the cup 10 and die 17 into indexed positions. However, to provide high speed manufacture, more precise alignment of the respective pole piece apertures 14 and better roundness in the punched cup 10, it is preferable to punch several apertures at one time. It has been found also if three punches such as 21, 22, 23 are spaced at 120 angles about the cylindrical cup workform 10 and radially pierce the cup, that the tendency to distort roundness of the cylinder is minimized. Thus, the die 17 and cylindrical workpiece can be moved to two ditferent stations for the pole piece aperture pairs 14 and to a third station whenpunches 24, 25, 26 are also used to produce the shield apertures16. Thus, the various punches are oriented respectively to pierce the cup workpiece 10 at angles illustrated in FIG- URE 2, but where at each station three punches separated by 120.are operated simultaneously. Since this substantially. equally distributes the stresses tending to distort. the cylindrical workpiece 10 from roundness, it has been found that the precise and critical tolerances imposed upon the dimensions, apertures and relative positions of elements in a convergence cup electrode can be met more readily in this preferred manner of punching than with prior art manufacturing techniques.

This multiple sequencing of punch triad sets at three different indexing stations is illustrated in FIGURE 3, where the outer stations B show the pole piece aperture punches 21, 22, 23 and the mid-station A shows the shield aperture punches 24, 25, 26. All punches are relatively positioned about the cup electrode workpiece 10 as shown by FIGURE 2. At each station a separate die post 17, 17' etc. is indexed in position by rotating table 30. The indexing mechanism is not shown since it may be any well known arrangement and may use a Geneva gear indexing principle for example, to index at eight stations. Only the three punching stations are shown herein as material to this present invention, but it is noted that the remaining stations which are not shown maybe used to load, orient, check and unload the workpieces 10 either manually or automatically.

Each of the punching stations is constructed in the manner shown by FIGURES 4 and 5, to constitute a hood assembly 35 which moves up and down along the axis 36 of the die'post 17 by means of either a cam or a power drive device such as a hydraulic ram (not shown) synchronized for operation to reciprocate coupling rod 38 at indexing stations A and B of table 30. At each station on table 30 is affixed a locator plate 30' to which is attached a replaceable die post 17 with registration bushings 39 for receiving pins 40 on the movable hood assembly 35. The locator plate 30' is loosely mounted in a floating position with tolerances in the order of .010" to provide accurate indexing alignment between pins 40 and bushings 39.

The punching hood assembly 35 moves from the normal unoperated position of FIGURE 4 into the limited punch position of FIGURE and back in the course of each punching operation at a respective index station. Thus, the hood assembly 35 moves in place with yoke 42 snugly over convergence cup cylinder 10, which may be registered in place on post 17 by means of a pin 43 extending through aperture 11.

An axially movable clamp-stripper plate 44 is loaded by spring 45, which is coaxially positioned about shank 46 and is seated at collar 47 on one end and on plate 44 at the other end. Thus, as the hood 35 moves downwardly and before the bottom limiting position of FIGURE 5, the clamp plate 44 engages the top of the electrode cup and clamps it to the top of post 17. Continuing downward motion compresses spring 45 until yoke 42 seats on the top of bushing 39 preventing further downward travel of this portion of the assembly at which point continued 4 downward travel of the hood shank 55 against the pressure of spring 65 causes pin and roller 53 to drive sliding punch plate 56 inwardly by means of cam slot '54, thereby piercing the respective apertures, thus completing downward motion.

Hood shank 55 then moves upwardly first withdrawing sliding punch plate 56, then engaging the head of the stripper bolt 58, which then lifts the inner assembly and yoke 42, withdrawing from cup 10, which is retained on post 17 by clamp stripper plate 44 acting through spring 45.

The Withdrawal of the punches is ensured by the action of the spring 65 around the stripper bolt 58 thrusting the inner assembly and hood shank 55 apart. As the hood then is withdrawn upwardly to perimt the head 66 of shank 46 to engage block 57, the plate 44 acts to release cup 10 from the yoke 42.

As shown in FIGURE 4, the punch 21 is in disengaged position. It is retained for lateral movement with respect to axis 36, as produced by means of cam peg 53 riding in cam slot 54. Thus, cam peg'53 is affixed to hood shank 55 which acts as a ram in its downward movement to force the punch laterally to pierce the workpiece cylinder 10 and come into the limiting position of FIGURE 5. The retainer guide for the sliding punch plate 56 may be a recessed bearing in block 57, for example, which is exactly registered in position by way of dowel pin 67 and receiving pins 40, bushing 39 and dowel pin 68. Alignment dowel pins 67 and 68 are alignment means for correct radial positioning of puncher 21, etc. to produce apertures 41, as relatively spaced about die post 17 and as gauged by pin-bushing assembly 3940. Yoke 42 is secured to block 57 by means of bolts (not shown) as correctly oriented by dowel pin 67. Thereby exact registration and maintenance of the tolerances required in the critical convergence cup dimensions and aperture shapes may be maintained.

By operation at the three illustrated punching stations in the maner described to produce nine spaced apertures in the convergence electrode cylinder 10, roundness is maintained as well as precision tolerances in shaping and positioning the apertures. This is accompanied by a very high speed automatic production of the convergence electrodes with relatively low cost machinery which is simple in operation.

Accordingly, it is seen from the detailed description of this automatic machine, that convergence electrodes may be made with improved precision. Those features believed descriptive of the nature and spirit of the invention are defined with particularity in the appended claims.

What is claimed is:

1. A machine for manufacturing convergence cup electrodes for catthode ray tubes having convergence pole pieces extending into a cylindrical body and comprising in combination, a punching station, a hollow die post positionable at said station and adapted to receive the cylindrical body of the workpiece about said die post,'a hood movable over said die post and workpiece to engage and hold a workpiece in place thereon, a laterally movable punch carried by said hood to move radially into and pierce said cylindrical body to produce an aperture shaped and positioned for inserting pole pieces to extend within the body, camming means for engaging said punch and moving it laterally, and a mechanism on said hood for engaging the camming means and sliding the punch through the cylindrical body after the hood has engaged the workpiece to hold it in place.

2. A machine as defined in claim 1, wherein three of said punches are located at intervals to move simultaneously through said body.

3. A machine as defined in claim 2, wherein the workpiece is a cup assembly having three beam apertures po sitioned symmetrically in a closed end and wherein at least two of said punching stations are provided, including means moving said die post from station-tO-station,

and means registering the cylindrical body on the post at the two stations to produce pole piece aperture pairs spaced to receive pole pieces extending into the body on opposite sides of the beam apertures.

4. A machine as defined in claim 1, wherein the die post has a plurality of diiferent apertures, and including means to position said cylindrical body for a plurality of different operations to register punches at dilferent apertures through the die post, and means successively moving punches radially through the different apertures in a sequence of different punching strokes.

5. A machine producing convergence electrodes for color cathode ray tubes comprising a set of three aperture pairs radially extended through the sides of a cylindrical electrode cup workpiece at 120 intervals to receive convergence pole pairs therein for each of three electron beams, said machine including an indexed table carrying a plurality of spaced posts for receiving said workpieces, a series of punching mechanisms located for operation at a plurality of indexed stations to which the posts are moved by said indexed table, each punching mechanism having at least one punch movable into the cylindrical workpiece radially to produce an aperture therein shaped to receive one of said convergence poles, wherein two stations are provided each with three punches spaced at 120 about said cylindrical workpiece to move simultaneously through said cylindrical workpiece and oriented to space the apertures for the pole piece pairs apart on opposite sides of said three beams.

6. A machine producing convergence electrodes for color cathode ray tubes comprising a set of three apertures pairs radially extended through the sides of a cylindrical electrode cup workpiece at 120 intervals to receive convergence pole pairs therein for each of three electron beams, said machine including an indexed table carrying a plurality of spaced posts for receiving said workpiece, a series of punching mechanisms located for operation at a plurality of indexed stations to which the posts are moved by said indexed table, each punching mechanism having at least one punch movable into the cylindrical workpiece radially to produce an aperture therein shaped to receive one of said convergence poles, wherein the workpieces are cup-like closed end cylinders for registration upside down upon said posts and including means for moving an assembly axially into said posts to clamp the workpieces by said closed ends into place on said posts before punching.

7. A machine as defined in claim 6, wherein the punches are carried by said assembly axially movable into the post and are laterally movable relative thereto, including camming means engaging the punches to move them laterally after the assembly clamps the workpiece on said post.

8. A machine as defined in claim 6 wherein each punching mechanism compries three punches radially positioned at substantially intervals about said workpiece, and means is provided for operating these three punches simultaneously.

Reierences Cited UNITED STATES PATENTS 

